DeVos going down would have been quite a blow to Trump's nascent administration. Presidents are usually given a level of deference from Congress' upper house. In all of American history, only nine cabinet nominees have ever been rejected by the Senate in a floor vote.

The most recent nominee to get the axe was John Tower. He was turned down from becoming Secretary of Defense by a 53-47 vote in the Senate in 1989, after being nominated by President George H.W. Bush. Tower landed in hot water after allegations about his personal misconduct. It was the first ever time in American history that one of a president's initial nominees was rejected. The times before that had been for replacement nominees later on in their administrations.

But Tower went down against a Democratic-led Senate that may have been disinclined to help out a Republican president. If DeVos or another nominee went down (still quite unlikely), it would be the first time in quite a while that a nominee was rejected not by a Senate controlled by the opposing party, but by the president's own. The last time that happened was in 1925, when President Calvin Coolidge's nominee for Attorney General, Charles B. Warren, went down after some Republicans joined the Democratic minority in rejecting him for being too close to the sugar industry and potentially corrupt.

One of the reasons outright rejection of cabinet nominees is so rare is that usually, a president will withdraw a nomination if it looks to be in jeopardy. That has happened 12 times in the history of the republic. The most recent was Tom Daschle, President Obama's nominee for Secretary of Health and Human Services, who withdrew himself from consideration after it was revealed he owed $140,000 in back taxes.

President Trump still has several cabinet nominees to get confirmed. The process has been slower than usual as Democrats have jumped on numerous potential issues with nominees. But even after the cabinet is finished, the administration will have to keep fighting these difficult battles. There are still 686 executive branch nominees that will require Senate confirmation, and 658 of them don't even have a nominee.